It was a quiet Tuesday in mid-August when the Edmonton Oilers announced that an Andrej Sekera-shaped hole had been blown through the middle of their defensive depth chart.

Sekera tore his Achilles tendon during summer training, and “underwent successful surgery.” It’s the second time in just over a year that the 32-year-old defenceman has suffered a major injury requiring surgery. A torn ACL in May 2017 sidelined him until December and sharply curtailed his effectiveness over the remainder of 2017-18.

An Achilles tendon injury can be a career-ender. A 2017 study by researchers at Columbia University Medical Center in 2017 found that of a group of 62 professional athletes with that injury, 19 (31 per cent) never returned to pro sports, and those who did make it back played fewer games and were less effective in the year following their return than comparable players who had not suffered the injury. Those negative effects did disappear in the second year following...